multi: move several wait group done calls to defer statements

chainntnfs/bitcoindnotify/bitcoind.go

@@ -174,6 +174,8 @@ func (b *BitcoindNotifier) startNotifier() error {
 // notificationDispatcher is the primary goroutine which handles client
 // notification registrations, as well as notification dispatches.
 func (b *BitcoindNotifier) notificationDispatcher() {
+	defer b.wg.Done()
+
 out:
 	for {
 		select {
@@ -436,7 +438,6 @@ out:
 			break out
 		}
 	}
-	b.wg.Done()
 }
 
 // historicalConfDetails looks up whether a confirmation request (txid/output

chainntnfs/btcdnotify/btcd.go

@@ -288,6 +288,8 @@ func (b *BtcdNotifier) onRedeemingTx(tx *btcutil.Tx, details *btcjson.BlockDetai
 // notificationDispatcher is the primary goroutine which handles client
 // notification registrations, as well as notification dispatches.
 func (b *BtcdNotifier) notificationDispatcher() {
+	defer b.wg.Done()
+
 out:
 	for {
 		select {
@@ -487,7 +489,6 @@ out:
 			break out
 		}
 	}
-	b.wg.Done()
 }
 
 // historicalConfDetails looks up whether a confirmation request (txid/output

lnwallet/btcwallet/btcwallet.go

@@ -781,6 +781,8 @@ func (t *txSubscriptionClient) Cancel() {
 // wallet's notification client to a higher-level TransactionSubscription
 // client.
 func (t *txSubscriptionClient) notificationProxier() {
+	defer t.wg.Done()
+
 out:
 	for {
 		select {
@@ -830,8 +832,6 @@ out:
 			break out
 		}
 	}
-
-	t.wg.Done()
 }
 
 // SubscribeTransactions returns a TransactionSubscription client which

lnwallet/wallet.go

@@ -425,6 +425,8 @@ func (l *LightningWallet) ActiveReservations() []*ChannelReservation {
 // requestHandler is the primary goroutine(s) responsible for handling, and
 // dispatching replies to all messages.
 func (l *LightningWallet) requestHandler() {
+	defer l.wg.Done()
+
 out:
 	for {
 		select {
@@ -450,8 +452,6 @@ out:
 			break out
 		}
 	}
-
-	l.wg.Done()
 }
 
 // InitChannelReservation kicks off the 3-step workflow required to successfully

peer/brontide.go

@@ -1836,6 +1836,8 @@ out:
 		}
 	}
 
+	// Avoid an exit deadlock by ensuring WaitGroups are decremented before
+	// disconnect.
 	p.wg.Done()
 
 	p.Disconnect(exitErr)